CLiFF Notes: Research In Natural Language Processing at the University of Pennsylvania

The Computational Linguistics Feedback Forum (CLIFF) is a group of students and faculty who gather once a week to discuss the members\u27 current research. As the word feedback suggests, the group\u27s purpose is the sharing of ideas. The group also promotes interdisciplinary contacts between researchers who share an interest in Cognitive Science. There is no single theme describing the research in Natural Language Processing at Penn. There is work done in CCG, Tree adjoining grammars, intonation, statistical methods, plan inference, instruction understanding, incremental interpretation, language acquisition, syntactic parsing, causal reasoning, free word order languages, ... and many other areas. With this in mind, rather than trying to summarize the varied work currently underway here at Penn, we suggest reading the following abstracts to see how the students and faculty themselves describe their work. Their abstracts illustrate the diversity of interests among the researchers, explain the areas of common interest, and describe some very interesting work in Cognitive Science. This report is a collection of abstracts from both faculty and graduate students in Computer Science, Psychology and Linguistics. We pride ourselves on the close working relations between these groups, as we believe that the communication among the different departments and the ongoing inter-departmental research not only improves the quality of our work, but makes much of that work possible

Low-Resource Unsupervised NMT:Diagnosing the Problem and Providing a Linguistically Motivated Solution

Unsupervised Machine Translation hasbeen advancing our ability to translatewithout parallel data, but state-of-the-artmethods assume an abundance of mono-lingual data. This paper investigates thescenario where monolingual data is lim-ited as well, finding that current unsuper-vised methods suffer in performance un-der this stricter setting. We find that theperformance loss originates from the poorquality of the pretrained monolingual em-beddings, and we propose using linguis-tic information in the embedding train-ing scheme. To support this, we look attwo linguistic features that may help im-prove alignment quality: dependency in-formation and sub-word information. Us-ing dependency-based embeddings resultsin a complementary word representationwhich offers a boost in performance ofaround 1.5 BLEU points compared to stan-dardWORD2VECwhen monolingual datais limited to 1 million sentences per lan-guage. We also find that the inclusion ofsub-word information is crucial to improv-ing the quality of the embedding

Human Feedback in Statistical Machine Translation

The thesis addresses the challenge of improving Statistical Machine Translation (SMT) systems via feedback given by humans on translation quality. The amount of human feedback available to systems is inherently low due to cost and time limitations. One of our goals is to simulate such information by automatically generating pseudo-human feedback. This is performed using Quality Estimation (QE) models. QE is a technique for predicting the quality of automatic translations without comparing them to oracle (human) translations, traditionally at the sentence or word levels. QE models are trained on a small collection of automatic translations manually labelled for quality, and then can predict the quality of any number of unseen translations. We propose a number of improvements for QE models in order to increase the reliability of pseudo-human feedback. These include strategies to artificially generate instances for settings where QE training data is scarce. We also introduce a new level of granularity for QE: the level of phrases. This level aims to improve the quality of QE predictions by better modelling inter-dependencies among errors at word level, and in ways that are tailored to phrase-based SMT, where the basic unit of translation is a phrase. This can thus facilitate work on incorporating human feedback during the translation process. Finally, we introduce approaches to incorporate pseudo-human feedback in the form of QE predictions in SMT systems. More specifically, we use quality predictions to select the best translation from a number of alternative suggestions produced by SMT systems, and integrate QE predictions into an SMT system decoder in order to guide the translation generation process

Hybrid machine translation using binary classification models trained on joint, binarised feature vectors

We describe the design and implementation of a system combination method for machine translation output. It is based on sentence selection using binary classification models estimated on joint, binarised feature vectors. By contrast to existing system combination methods which work by dividing candidate translations into n-grams, i.e., sequences of n words or tokens, our framework performs sentence selection which does not alter the selected, best translation. First, we investigate the potential performance gain attainable by optimal sentence selection. To do so, we conduct the largest meta-study on data released by the yearly Workshop on Statistical Machine Translation (WMT). Second, we introduce so-called joint, binarised feature vectors which explicitly model feature value comparison for two systems A, B. We compare different settings for training binary classifiers using single, joint, as well as joint, binarised feature vectors. After having shown the potential of both selection and binarisation as methodological paradigms, we combine these two into a combination framework which applies pairwise comparison of all candidate systems to determine the best translation for each individual sentence. Our system is able to outperform other state-of-the-art system combination approaches; this is confirmed by our experiments. We conclude by summarising the main findings and contributions of our thesis and by giving an outlook to future research directions.Wir beschreiben den Entwurf und die Implementierung eines Systems zur Kombination von Übersetzungen auf Basis nicht modifizierender Auswahl gegebener Kandidaten. Die zugehörigen, binären Klassifikationsmodelle werden unter Verwendung von gemeinsamen, binärisierten Merkmalsvektoren trainiert. Im Gegensatz zu anderen Methoden zur Systemkombination, die die gegebenen Kandidatenübersetzungen in n-Gramme, d.h., Sequenzen von n Worten oder Symbolen zerlegen, funktioniert unser Ansatz mit Hilfe von nicht modifizierender Auswahl der besten Übersetzung. Zuerst untersuchen wir das Potenzial eines solches Ansatzes im Hinblick auf die maximale theoretisch mögliche Verbesserung und führen die größte Meta-Studie auf Daten, welche jährlich im Rahmen der Arbeitstreffen zur Statistischen Maschinellen Übersetzung (WMT) veröffentlicht worden sind, durch. Danach definieren wir sogenannte gemeinsame, binärisierte Merkmalsvektoren, welche explizit den Merkmalsvergleich zweier Systeme A, B modellieren. Wir vergleichen verschiedene Konfigurationen zum Training binärer Klassifikationsmodelle basierend auf einfachen, gemeinsamen, sowie gemeinsamen, binärisierten Merkmalsvektoren. Abschließend kombinieren wir beide Verfahren zu einer Methodik, die paarweise Vergleiche aller Quellsysteme zur Bestimmung der besten Übesetzung einsetzt. Wir schließen mit einer Zusammenfassung und einem Ausblick auf zukünftige Forschungsthemen

Graduate course catalog (Florida International University). [2016-2017]

This catalog contains a description of the various policies, graduate programs, degree requirements, and course offerings at Florida International University during the 2016-2017 academic year.https://digitalcommons.fiu.edu/catalogs/1072/thumbnail.jp

Graduate course catalog (Florida International University). [2015-2016]

This catalog contains a description of the various policies, graduate programs, degree requirements, and course offerings at Florida International University during the 2015-2016 academic year.https://digitalcommons.fiu.edu/catalogs/1067/thumbnail.jp